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HW 90 Pump & Adapter !

Hi, I bought a HW90 a short while ago, It was making 9 Fpe,
I was loaned a Theoben hose & pump by one of the forums " Gentlemen "

He did mention that one of his Gas ram rifles he could only pump to 10 Fpe because of the effort required,
Now the pump & the hose are not of the quality you would expect from
Theoben ???? I never tried the Theoben pump.

Its an adapter to fit the Stirrup pump, I started to pump it to 15 Bar, Tried still the same, A couple more Bar, Still the same, A little more, No change,
I thought I would try 22 Bar ish, ( I say " ish " ) because the gauge on the pump is 0-250 Bar & difficult to add 1, or 2, more !
And " Wow "

You could feel the difference in cocking, But shooting it felt the same, Recoil & noise were the same ! ( It does have a moving Inertia weight to reduce recoil ) I read on one site its decribed as Semi-recoiless !
The 80 doesn,t have one !

By judicious tapping of the Schrader valve, I was able to release pressure & drop the output to 11.8 Fpe ( I just bet, Someone will come on & say thats too close, ) Maybe that will stop them .

The stirrup pump required no effort at all, All connections were only finger tight, A very simple task,
I was thinking I might make up a batch ( Gun to stirrup pump ) But I have to buy some parts to make them, What do you think ! Ged.

I have to agree that the HW pump is a Heath Robinson affair. I have found that you need to give it about ten good pumps to charge the pump and line before it starts to fill the cylinder. Without a gauge it is hit or miss to know the right amount (see one of my first posts about letting fly with a super sonic .17 pellet in the back garden!) I also found that tapping the release valve can dump the whole lot in one go too!

Certainly the stirrup pump is the way forward and I'm suprised no-one has made an adaptor for the HW90 et al before. I'm sure you'll have a few interested parties for it. Good work fella.

Adaptor

I have been using a similar setup with my Logan stirrup pump for a few years now. Once a year I strip, clean, check/replace the O rings and tophat, relube and then pump it up to give me +- 11.4fpe with webley mozzies. I agree 11.8 is a little high if your using a heavy pellet as with a lighter pellet you'll be over the top. Better be SAFE than sorry
Cheers and safe shooting
Gary

Sorry about the late reply, only just found the info. What size is the adaptor to fit the HW90 rear end? Just bought a couple of adaptors which were supposed to fit, they were sent as 1/8" to 1/8" BSP male/male, but I reckon they are more like 3/8". It fits the stirrup pump hose no probs but far too big for the female schrader housing. Thanks in advance. Gordon